Today there are numerous commercial products that contain both an antihistamine and decongestant. These products may have less tendency to cause sedation because of the decongestant factor and thereby can offset, in some cases, the sedative aspect of the antihistamine. It has been further determined that these products vary substantially in their duration of action thereby offering inconsistent results to the public at large.
Although it is known that antihistamines do not prevent or cure the common cold they are found in many cold remedies. As stated in the "Handbook of Non-Prescription Drugs, 9th edition," "Antihistamines are chemical agents that exert their effect in the body primarily by competitively blocking the actions of histamine at receptor sites. Those antihistamines that block the H.sub.1 receptor are potentially useful treating allergic rhinitis and, to a lessor extent, colds."
Some of the most commonly used non-prescription antihistamines are selected from the group consisting of brompheniramine maleate, chlorpheniramine maleate, doxylamine succinate, phenindamine tartrate, pheniramine maleate, promethazine maleate, pyrilamine maleate, thonzylamine hydrochloride, and mixtures thereof. These compounds are recognized by the Food and Drug Administration (FDA) over-the-counter (OTC) advisory review panel on cold, cough, allergy, bronchodilator, and antiasthmatic drug products as being safe for non-prescription use and effective in suppressing the symptoms of allergic rhinitis when taken in the dosage specified. Among the above-mentioned non-prescription antihistamines it is known that chlorpheniramine maleate possesses relatively weak sedative properties. Due to its weak sedative properties chlorpheniramine maleate enjoys widespread use in numerous combination decongestant/antihistamine products.
Decongestants, when applied intra-nasally, are known to provide relief of nasal congestion. This decongestant action is accomplished by the shrinking of the mucous membrane which makes the breathing process easier along with allowing the sinus cavities to drain.
As with antihistamines there are recognized decongestants for (OTC) products such as those selected from the group consisting of naphazoline hydrochloride, ephedrine, oxymetazoline hydrochloride, phenylephrine hydrochloride, xylometaxoline hydrochloride and mixtures thereof. The FDA advisory review panel on cold, cough, allergy bronchodilator, and antiasthmatic drug products has recommended these ingredients as safe and effective at appropriate recommended controlled dosage rates.
Additionally, many other ingredients have been added to cold products which fall into the category of aromatics composed primarily of natural oils or extracts therefrom such as camphor, eucalyptus oil, menthol, azulen and mixtures thereof.
With many antihistamine and decongestant products a preservative is required to insure the stability of the finished product. Benzalkonium chloride has been found to be used in many pharmaceutical preparations and is recognized as safe when used at the recommended and used dosage rates.
Several problems have heretofore plagued the field of antihistamine/decongestant nasal sprays. One problem is a failure of the formulations to provide relief for a desired time interval. This results in misuse of the formulations in the form of overdosing. This leads to the second problem which is termed "rebound congestion". This is a phenomenon which occurs when, largely due to overdosing or a prolonged usage period, acute nasal congestion manifests itself as the effects of the antihistamine/decongestant diminish.
It is therefore an object of the present invention to formulate an antihistamine and decongestant that optimizes the desired prompt and prolonged effect.
It is a further object of the invention to formulate an enhanced antihistamine/decongestant nasal spray that does not provoke rebound congestion.
It is a still further object of the invention to provide a method for treating nasal congestion which results in enhanced decongestant action and surprising curative effects.
Yet another object of the invention is to provide a method of treating rhinitis or sinusitis by incorporating the novel compositions of the invention into a container adapted to deliver a controlled dosage amount, for example via a spray or a specific number of drops. The controlled dosage amount is calculated so as to be effective to administer the required ingredients within their prescribed parameters of use when said controlled dosage amount is applied to the effected nasal and sinus passages.
Other objects and advantages of this invention will become apparent from the following description.